Conventionally an element for an upright toaster comprises a former of an electrically non conductive material and an electrically conductive tape wound continuously round the former with each run thereof extending between grooves in the opposite side edges of the board or each half of the board. The conductive tape is exposed except that one or more narrow strips of non-electrically conductive material are frequently located outside the tape running from top to bottom of the former, and spaced from the side edges, to limit the amount of outward bowing of the tape and to prevent the tape flying outwards if it breaks.
A toaster comprises a plurality of such elements which could be connected in parallel or in series. Because the conductive tape is exposed and can be easily touched by anything inserted into the toaster slots it is a requirement that the toaster must be double pole switched. This increases the cost of the toaster particularly if any electronics are incorporated in the toaster. It is also a requirement for upright toasters that an array of guard bars to prevent toast contacting the elements and which define the toaster slot are spaced at least 4 mm from the tape (since this is likely to bow outwardly when hot).
Conveyor toasters or other cooking apparatus in which elements are located horizontally conventionally also have live conducting tape or strip exposed, and suffer from uneven heating across the width of the apparatus.